Magnetically-controlled switch.



H. L. VAN VALKENBURG.

MAGNETICALLY CONTROLLED SWITCH.

mwucmou FILED APR. 1. 1916.

1 ,297,979 I Patented Mar. l8, 1919.

UNITED srArEs PATENT orricn HERMON L. van VALKENBURG, or MILWAUKEE, WISCONSIN, nssrcrvon 'ro INDUS- TRIAL coivrnotnnn COMP NY, or MlLWAUKEE, WISGONSIN, A CORPORATION or WISCONSIN.

MAGNETICALLY-CONTROLLED SWITCH.

, Application filed April 7, 1916. Serial No. 89,684.

' To all whom it may concern:

Be it known that I, HERMoN L. VAN VALKENBURG, a citizen of the United States, residing at Milwaukee, in' the county of Waukesha and State of Wisconsin, have invented a certain new and useful Improvement in Magnetically-Controlled Switches, of which the following is a specification.

My invention relates to magnetically controlled switches intended primarily to be used in connection with motor starters. The general object of the invention is to provide electromagnetic means for automatically operating the switch element when the current reaches a preordained critical value. One of the specific objects is to provide a construction by which, when the current falls below a given value and the switch element moves, the holding action of the device will be augmented. In the design illustrated, there is a main operating and also a lookout coil, and when the lookout coil lets go, its plunger moves into the field of influence of the operating coil which supplements the action of the plunger of the operating coil. Another object is to provide means for regulating the action of the device.

I obtain my objects by the mechanism illustrated in, the accompanying drawings, in which- Figurl is a central vertical section of a switch embodying a component part of the invention. In this figure the elements are shown in the position which they will assume when the circuit is dead.

Fig. 2 is similar to Fig. 1, and shows in full lines the positions which the parts will assumewhen energized by a current of comparatively high value. The. dotted lines in dicate the position which the parts will assume when the energizing current falls below the critical value.

Fig.3 i a top plan of the parts shown in Figs. 1 and2. a

Fig. 4c is a diagram illustratin the principle of operation, of one type 0 controller employing the switch of Figs. 1, 2 and 3.

In the accompanying drawings, which illustrate certainforms which my invention may assume, similar reference characters de-' note similar parts throughout the several views.

Referring first to Figs. 1, 2 and 3: A. panel Specification of Letters Patent.

1 of slate or other insulating material supports two contacts 2, 3, these representing the two terminals of a supply circuit. These contacts are secured to the panel in any suitable manner and are energized through the The parts are so arranged that when the rod raises the contactor, said contactor will bridge the contacts 2 and 3.

Rod 8 is here shown to be arranged vertically and to be vertically movable, being guided at the upper end by a bushing 9 carried by the upper horizontal arm of a frame 10, which, when viewed in vertical section, is U-shaped, and attached at the back tov the panel by means of a bolt 12 or other appropriate fastening means. This frame is of iron or other material of magnetic permeability and supports an operating or main coil or winding 13 between its upper and lower branches. By preference, this coil is lined with tubing 14 of brass or a suitable substitute-this tubing is shown to be outwardly flanged at the top and bottom with the flanges inserted between the horizontal arms of the frame 10 and the end disks 15, 15 of said operating coil. A second tubing 17, preferably of brass, is fitted within the tubing 14 and extends down into the second magnet frame 20, which is similar to the first frame 10, except that it is shorter. It is fastened to the panel by a stud 22 or other suitable fastening device. The coil 21, which I shall refer to as the holding coil or lockout coil has terminal disks 23 of insulating material. Coil 21 is lined by a tube 24 similar to the tube 14 of the operating coil 13. A core 27 fits slidingly within the inner guide tube 17 and is rigidly fastened to the lower end of rod 8. Normally said core, which may be termed the holding core seats upon a sto which here assumes the form of a brass co lar 27. A screw 28 of iron or other metal having high permeability screws into the lower arm of frame 20 and is held locked in proper position by a nut 20. By adjusting, said screw,

the air gap between it and the holding core 27 may be varied, thus regulating the point at which the holding coil will release.

Above the holding core 27 is an element 32, which may be designated as the operatupper end of the operating core 32, to pre vent sticking to the part 9 of the frame due to residual magnetism. Said operating core is longitudinally chambered from the top to a point near the bottom and at the bottom -said core is apertured to accommodate the rod 8 and permit independent Vertical move-- ment of the rod and operatmg core. A hellcal compression spring 36 encircles the rod 8 and at thelower end. seats upon the bot tom of the chamber formed within the-0perating core. At the upper end said spring engages the under side of a collar 38, which is rigidly fastened to the rod.

Now describing the operation ofthe unit shown in Figs. 1, 2 and 3: When the coils are unenergized, the two cores 27 and 32 remain down and the switch stands open as shown in Fig. 1. If, new, a current of comparatively high value passes through the coils, the holding coil 21 will hold down its core 27 but the operating coil 13 will raise its core 32 and compress spring 36 as shown in Fig. 2. Under these conditions the switch remains open. If the energizing current thereafter drops below a certain predetermined point, the holding coil will be weakened to such an extent that it will be no longer able to hold down its core in opposition to the force of the spring, and the holding core and the contactor 6 attached thereto will rise. As the holding core rises, it comes into the magnetic field of the operating coil, which exerts a strong upward pull upon it, and firmly closes the switch. In practice the parts are so de signed that when the switch is closed the spring will be compressed to only a slight extent, if at all, while the operating coil will exert a strong upward pull on the contactor. The result is that the device is very positive in its action and the contactor is held in firm and close contact with the terminals 2, 3.

Referring now to the diagram of Fig. 4, in which the above described switching .unit is employed:

R, R and R represent three sections of starting resistance, which in the present instance are in series with the armature M of the motor. The conductors S and S represent the opposite sides of the supply circuit and these conductors are controlled by manually operated switches 8 and 8 respecconductors f and f connected in. th

conductors 50,- 51-and 52 to the resistance tively to the operating coil 13 and the l switch unit B; said. coil is connects of the switch unit C. The other end oi L- 0011 is connected by a conductor 7i 5 directiy 1 .1% to the-conductor 72. A resistance 76 is cennaesgere tively. The field oi the meter Y shown as a shunt field, energized hereinafter described.

A, B and C represent three units tailed in Figs. 1, 2 and 3. Tracing circuits, the switch 8 is connected thri At the other end, said resistance is con by a conductor 53 to one of the tocontacts 54. A conductor 55 leads tact 54 to the operating'coil a of ti... switch A. Coil a is connected in series the coil a these coils corresponding re.

ing coil 21, shown in Figs. 1 and 2. coils operate the contactor 56 in the ner in which the coils 13 and 21 one. contactor 6 oflTigs. 1 and 2. cm 57 connects the holding coil (0 to ow of the resistance R The other end c resistance is connected to the resistanc and also to the conductor 58 WlliC-J. lean the coil 0 of the switch C. Said coil c sponds to the holding coil-21 of t. shown in Figs. 1, 2 and 3. The otlr of the coil 0 is connected by a con; 59 to the stationary contact 60,.which part of the switch unit B. The s contact 61 forms a companionteran f the contact 60 and is in position to be nected therewith by the contactor 6 switch unit B. Contact 61 is cm through a conductor 32 to the st. contact 63 which forms a compani minal to the stationary contact c switch unit A. A conductor 6 lcr conductor 62 to the operating coil 0 to the holding coil of switch nn' other end of the holding coil 6 is connect by a conductor 65-to the conductor 50. resistance R? is connected by a conduct to the stationary contact 67 which tern of the terminals of the switch unit C.

contact is in position to be engaged b contactor 68 of the switch unit C. ii.

tact 69 forms a companion terminal "1. contact 67 and is connected to the cent 51 by the conductor 70. Contact ti? nected by the conductor 71 to one te of the armature M of the motor; t e 0 terminal of the armature is connected conductor 72 to the switch s An contact 73 is provided in the unit 2&3 in sition to be engaged by the contaetor TlllS auxiliary contact is connectedby ductor 74: to one end of the operating Ct shunt circuit is protected by suitable resistance. The field conductor f, previously mentioned, is connected to theconductor 7 2 and the field conductor f is connected to' 5 the conductor 65. When the parts are connected as shown in Figwf, the operation is as follows:

en the operator wishes to start the motor he moves the hand switches s, s to closed position. Prior to closing these hand switches, the switch units A, B and C, being totally unenergized, will stand in open position shown in the diagram; but as soon as switches 8, 8 are, closed, full initial starting current will flow through the conductors 50,

51 and 52 to the resistance R, thence through the conductors 53 and 55, through the series coils a, a thence through the conductor 57 to the resistances R and R thence through the conductors 66 and 71, through the arma- "ture M, out through the conductor 72 and switch 8 to the opposite supply conductor 1 S As the motor is initially standing still it will at first be creating no counterelectromotive force and hence the current flowing through thecontrolling apparatus will be at 'a maximum so far as permitted by the resistances which are incircuit. With the current thus at a maximum value, the holding coil a will'be able to hold the contactor 56 down in open position notwithstanding the fact that the operating coil a will, in accordance with the principle illustrated in Figs. 1 and 2, raise its inclosed core and compress its inclosed spring. But as the motor commences to speed up it creates a counterelectromotive forceuntil the current falls below the critical value and weakens the electromagnetic effect of the holding coil a to such an extent that the inclosed spring in the operating coil 0 overcomes the holding effect of the coil a and brings the 'contactor 56 to closed position. This short-circuits the resistance R and the current will flow from switch 8 through the conductors 50 and 65, through the coils b and b of the swich unit '13; thence it flows through the conductor 64 and contactor 62 to thekcontact 63, whence is led into the contactor 56, which is now in closed position, to the stationary contact 54; thence through the conductor 55 and coils-a and a and conductor 57 to the resistances R and R and out through the armature. The current continues to flow along this path until the motor, in increasing its speed, reduces the current to a value below the point where the holding coil 5 willhave sufficient electromagnetic influence to maintain the contactor 62 in open position. Thereupon, said contactor rises and bridges the contacts 61, 7 3 and 60. This cuts out the resistance R. for the current will now flow through the con ductors 50 and 65 and coils b and 12 through the contactor 62 to the contact 60. whence it will flow through the conductor 5.9 and coil 0 to he conductor 58, thence through the resistance R and thence out through the motorarmature to the opposite side of'the line. When thisstatus is reached, the operating coil 0 will be energized through the conductor 74 which is connected by the conductor 7 5 directly to the opposite side of the line instead of being connected through the motor. When the speed of the motor approaches maximum and the current in the coil 0 falls below the critical value, the contactor 68 moves to closed position. This short circuits all of the starting resistance andalso puts the coil'c in a shunt circuit, consistingof the resistance 76, coil 0 and conductor 7 5, thus holdingthe last switch closed regardless of the, fluctuations in the arma ture circuit; in fact the current in the armature circuit may even be momentarily reversed without affecting said switch.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is v 1. An electro-magnetically operated switch having a movable switch element, two magnetic plungers mechanically connected there to, and a separate coil for each plunger adapted, when energized, to pull in opposite directions, the plunger of one coil, when the other predominates, moving away from its own coil and toward and into the magnetic field of the other coil.

2. An electro-magnetically operated switch having a movable switch element, two magnetic plungers mechanically connected thereto, a separate coil for each plunger adapted,

when energized, 'to pull'in opposite directions, the coil being in series and one being stronger than the other whereby it may, un- Y der certain conditions, predominate over the weaker coil, the plunger of the weaker coil, when the stronger predominates, moving away from its own coil and toward and into the magnetic field of the stronger coil.

3. An electro-magnetically controlled switch having two windings, each having a plunger movable relatively to it. for coperatively controlling the switch element, the windings tending, when energized, to influence the plungers oppositely, and one of the plungers being normally remote from the field of the other winding but movable thereinto for producing acumulative effect upon the switch element.

4:. An electro -magnetically controlled switch having a movable switch element and two plungers for actuating it, each plunger having a seperate winding of its own, the plungers and windings being relatively movable, and the two windings, when entergized, producing opposite effects upon their plungers, one winding being stronger than the other and the plunger of the weaker winding being normally practically out of the field of the stronger winding but 13.0.

moving thereinto to produce a cumulative I force upon the switch element [When the weaker winding .has been deenergized to 'ing for operating said plunger, a holding plunger for preventing the actu tion of the switch element notwithstanding the force of the spring, and.- a holding. winding cooperating withsaid holding plunger, said spring, when said holding "winding becomes de'e'nergized to. such an extentthat it cannot overcome they force ofthe spring, moving the plunger of the holding winding into the field of the first mentioned winding.

I I I I "Iment, a spring, a plunger in the maln coil 7 adapted when its 'coil is energized to-strain 6. A magnetically controlled switch having a main coil, a lockout coil, a switch elesaid spring to thus urge the switch element forward, a plunger in the lockout coil adapted when its coil is energized to urge the switch element backward, and mechani cal means for regulating the maximum effort that the lookout coil can exert on its punger for any given value of energization of the lockout coil.

7. A magnetically controlled switch having a main coil, a lookout coil, a switch elej merit, a spring, a plunger in the main coil' adapted, when its coil is energized, to strain said'spring to thus urge the switch element forward, a plunger in the lockout coil adapt-- ed, when its coil is energized, to urge the switch element backward, and an adjustable stop fixed with reference to the lookout coil for regulating the distance to which the whereby to regulate the maximum effort that the lookout coil can exert on its plunger for any given value of energization.

8. A magnetically controlled switch hav-' ing 'a main coil, a lookout coil, a switch element, a spring, a plunger 1n the main coil,

adapted when its coil is'energized to strain said spring tothus urge the switch element forward, and a core in the lockout coil adapted", when its coil is energized, to urge the switch element backward, the two coils being in series and being so designed that at any given value of current the pull which the main coil exerts upon its plunger is greater than the pull which the lookout coil exerts upon its plunger.

9. A magnetically controlled switch having a main coil, a lookout coil, a switch element, a spring, a plunger in the main coll adapted, when its coil is energized to strain said spring to thus urge the switch element forward, and a plunger in the lockout coil adapted, when its coil is energized, to urge the switch element backward, the two coils being in series, and so wound that their.

magnetic fluxes oppose each other, said coils being so designed that the main coil exerts a greater pull upon its plunger than the lockout coil does upon its plunger for any given value of current, and the coils being so close together that when the lockout coil releases its plunger it enters the magnetic above a predetermined point holding its core in position to hold the switch open'i'n" opposition to the force of the spring, said holding coil when energized below said pre-" determined point exerting insufficient influence upon its core to resist the force of the spring, and mechanical means for regulat ing the maximum amount of pull which the holding coil can exert upon its core with any given amount of'energization of said holding coil.

11. In" combination, a normally (LP/81,1"

switch, a spring for closing said switch, a

movable core, an operating coil, which, when energized, moves said core to a position to strain said spring and thereby urge the switch toward closed position, a holding coil having a movable core mechanically "-connected to said switch, said holding coilwhen energized above a predetermined point holding itscore in position to hold the switch open in opposition to the force of the spring, said holding coil when energized below said predetermined point exerting insufiicient influence upon its core to resist the force of the spring, and a stop for limiting the extent to which the holding core can enter into said holding coil.

12. In combination, a normally open switch, a spring for closing said switch, a movable core, anoperating coil, which, when energized, moves said core to a position to strain said spring and thereby urge the switch toward closed position, a holding coil having a movable core mechanically connected to said switch, said holding coil when energized above a predetermined point holding its core in position to hold the switch open in opposition to the force of the spring, said holding coil when energized below said predetermined point exerting insufficient influence upon its core to resist the force of the spring, a stop for limiting the extent to which the holding core can enter the holding coil and a stationary core at one end of the holding coil, said stationary core being adjustable toward and f m the movable h ding core to thereby vary the air gap between them and regulate the conditions under which the movable holding core will' be contactor toward closed position, a holding coil having a movable core connected to said contactor for holding said contaotor open when said holding coil is energized above a predetermined pomt and for releasing said holdin core when said holding coil is energized low said predetermined point, said coils being separate but arranged endwise whereby said holding core moves into the field of the operatin coil when released by said holding coil, an is urged by said operating coil in a direction to close the contactor.

14. In a-switch unit, a contactor, a spring for urging it to closed osition, an operating coil having a movab e core for straining said spring, a holding coil having a movable core mechanically connected to said contactor for holding the contactor in open position in oppositlon to the force of the spring when the holding coilis energized above a certain degree and for releasing said holdin core when said holding coil is energized be 0w said degree, said co1ls being separate but arranged endwise, and the holding core when released movin into the field of the operating coil where y the operating coil thereupon urges the contactor toward closed position.

15. In a switch unit, a contactor, an operating coil having a core for urging sald contactor toward closed position, a separate holdin ing coil an having a movable core connected to said contactor for holding said contactor open when said holding coil is energized above a predetermined point and for releasingsaid holdin core when said hold ing coil is energize below said predetermined point, said coils being arranged endwise w ereby said holding core moves into the field of the operating coil when released by said holding coil, the holding coil being mechanically limited in its movement away from said operating coil, said holding coil also having a stationary core at one end of the holding core, and the stationary core being adjustable toward and from the holdcoil in series with the operating core to vary the air gap between them and thus vary the releasing point of the holding coil.

In witness whereof I have hereunto subscribed my name. a v

HERMON L. VAN VALKENBURG.

copies 0! this patent may be obtained for five cents each, by droning the "flonmil'slour o! lhtentl, Washington, D. 0. 

